Politico describes the signs as a “gallows humor” effort by campaign manager Robby Mook, but it’s also important security advice during an election cycle in which hacks and leaks have dominated headlines.

In recent weeks, WikiLeaks has posted caches of what it says are messages from Clinton campaign chair John Podesta’s personal Gmail account. And there's at least one glaring password security mistake among the emails leaked so far: Podesta had his former assistant email him his Apple ID and password.

Users on the /pol/ board of 4chan — a mostly anonymous forum where members are fond of posting pro-Donald Trump memes — discovered the log-in information quickly and claimed to have used it to remotely wipe Podesta’s Apple devices.

Podesta’s Twitter account was also hacked to display a tweet supporting Trump’s candidacy that also contained an apparent reference to the /pol/ board.

But the Podesta emails are just the latest in a string of hacks that have primarily targeted the Democratic Party, including a breach at the Democratic National Committee that resulted in then-chairwoman Rep. Debbie Wasserman Schultz's (D-Fla.) resignation.